The present inventor has observed that there are classes of bugs in microprocessor designs in which the microprocessor gets hung (i.e., it is no longer retiring instructions) because a deadlock or livelock condition has occurred at one of the cache memories of the microprocessor. For example, a bug may cause the processor to be unable to answer an external snoop of its caches and consequently “snoop stall” indefinitely, which has the effect of blocking the bus from performing any further bus cycles (i.e., a “bus hang”). For another example, a bug may cause the processor to be unable to drive data in response to a snoop and “DBSY stall” indefinitely, which also causes a bus hang. Such bugs may obviously have detrimental effects in a computing system that includes the microprocessor. Furthermore, such bugs may be difficult to debug if the microprocessor stays in the deadlock/livelock condition. What is needed is a way to break the deadlock/livelock situation.